It is common practice to manufacture cylinder blocks for internal combustion engines out of aluminum because of the weight reduction benefits gained. However, the material properties of aluminum require that a liner of a different material, usually cast iron or steel, be inserted into the cylinder bores in order to withstand the heat and forces generated within the cylinder. There are several methods of inserting the liner, dependent on the material used for the liner and the thickness of the liner, among other factors.
For example, it is beneficial to have a thin walled liner to improve thermal conductivity and reduce weight. The commonly used methods to insert thin walled liners involve either heating of the cylinder block to cause expansion while simultaneously cooling the liner to cause shrinkage, and then inserting the liner into the cylinder to produce a shrink fit, or forming a sheet of material into a cylindrical liner and inserting the liner into the bore using a interference press fit over the entire distance of the cylinder bore, as described in British Patent Specification 1395220.
The inventor of the present invention has found certain disadvantages with these prior art insertion methods. Primarily, high energy levels are required to accomplish insertion and the types of materials that can be used are limited. With respect to the interference press fit method described, application of high load is required to force the interference fit over the entire height of the cylinder liner resulting in high energy expenditure requirements. This method also requires that either an internal support be provided, or that the thickness and material of the liner be sufficient such that the liner does not buckle on insertion.